The objectives of this proposal are to identify the regulatory mechanisms by which the adrenal cortex is controlled by ACTH. Toward this end a study of a family of cAMP-binding proteins (several of which are increased in concentration by ACTH) is being made. The subcellular localization of these proteins is being examined by photoaffinity labelling and conventional subcellular fractionation techniques. Their function will be studied by determining their relationship to protein kinase and phosphodiesterase activities and by examining their effects on cholesterol transport to mitochondrial P450SCC and upon the catalytic activity of this enzyme.